While shade structures exist, and are provided in many environments, they tend to be rigid, expensive, and permanent or time consuming to erect. This is especially true for shade structures for shading large areas, which tend to take the form of permanent rigid structures, as in, for example, a pavilion constructed out of wood, as might be seen at a public park. The permanent construction of or selective setting up and tearing down of a shade structure increases the cost thereof, making the provision of shade in some areas impractical. Because there are many areas that would benefit from being better shaded, there exists a need in the art for new efficient designs for the provision of shade structures.
Shades for large areas are of particular interest. In sunny areas, motor vehicles sitting out in the sun, for instance, in parking lots, become extremely hot and uncomfortable after a few minutes time, and can remain that way for the first few minutes of operation, until an air conditioner is put to use or until cooling air circulates through open windows. The discomfort of entering a hot vehicle left in the sun is well known to everyone, even in moderate climates. The vehicles become so hot, in fact, that it is well know that pets and children can suffer injury and even death from being left in a car in hot weather. Yet very few parking lots are shaded, due to the cost of the structure that must withstand wind loads of 70 mph winds and higher.
Retractable shade structures, such as awnings, provide a cost-effective, lightweight method of shading small areas. They can be retracted automatically when high wind speed is detected. Retractable awnings have typically been used to extend from the sides of buildings and generally have an extendable limit of less than five meters. They are typically extended from the same side on which they are mounted. To cover large areas with a retractable awning will require that the typical extension distance to be greatly increased, at least by a factor of 2 or 3, and perhaps as much as 5 to 10. A new and novel structure is needed to achieve this.
For larger structures, the tensioning of the shade structure is important, because a shade structure that is not sufficiently taut may be easily damaged or otherwise compromised by weather and wind conditions. Thus, there further exists a need for shade structures that are configured to achieve sufficient tensioning to remain structurally sound in at least moderate weather conditions, although it is envisioned that such shade structures could be beneficially retractable to protect them against more severe conditions.
Of particular interest are retractable awnings that extend from a roll. And as a large retractable awning is extended further from the roll, the need to maintain and control proper tension within the awning fabric becomes more important. There is a need in the art for a novel structure to ensure proper tensioning throughout its extendable range. The longer extension distances also necessitate an automatic retraction ability to prevent damage in high winds. Preferably such retraction could be accomplished without the need for power. There is a need in the art for improved automatic retraction methods for large retractable awnings.
Further, there is a need to cover large areas with solar cells that can generate photovoltaic power. Traditional solar cells have been the rigid crystalline silicon type, which require rigid structures, such as the roofs of buildings, on which to be mounted. Some such structures have been used for parking areas, but the cost of the structure with the cost of the traditional solar cells have been prohibitive.
New solar cells are on the verge of commercialization that can be printed or fabricated inexpensively with roll-to-roll technology onto thin flexible fabrics or polymers. The combination of these low-cost, lightweight flexible solar cells to a low-cost retractable shade structure could provide an economical solution to the mounting energy and global warming problems. Photovoltaic power is widely recognized as one of the most environmentally attractive of all energy sources, but the structures and methods for employing solar cells that produce photovoltaic power have not yet proved viable. Thus, there is a need in the art for a novel structure to electrically connect the solar cells on a large rotatably retractable awning.